JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2022, Vol. 46 ›› Issue (6): 271-278.doi: 10.12302/j.issn.1000-2006.202207037

Special Issue: 南京林业大学120周年校庆特刊

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Effects of exogenous signal substances on growth and photosynthetic characteristics of Santalum album seedlings

LI Zhenshuang1,2(), WANG Qian1, ZHU Yuan1, YANG Fucheng1, LIANG Junfeng1, LU Junkun1,*()   

  1. 1. Research Institute of Tropical Forestry, Chinese Academy of Forestry, Key Laboratory of National Forestry and Grassland Administration on Tropical Forestry Research, Guangzhou 510520, China
    2. Nanjing Forestry University, Nanjing 210037, China
  • Received:2022-07-25 Revised:2022-09-17 Online:2022-11-30 Published:2022-11-24
  • Contact: LU Junkun E-mail:zhenshuangli@caf.ac.cn;junkunlu@caf.ac.cn

Abstract:

【Objective】Root exudates play an important role in the plant interspecific relationship. The effects of host root exudates and chemicals on growth, root development, nutrient accumulation and photosynthetic characteristics of hemiparasitie Santalum album seedlings were studied. The superior host root exudates or several chemicals were screened to provide a scientific guidance for cultivating S. album seedlings.【Method】Under greenhouse conditions, we performed the pot experiment to determine whether root exudates (Acacia confusa, Bischofia polycarpa, Dalbergia odorifera, Dracontomelon duperrereanum and S. album) and haustorium-inducing chemicals (2,6-dimethoxy-p-benzoquinone (DMBQ), formononetin, quercetin and syringaldehyde) could promote the growth and root development of S. album seedlings. The growth indices (height, diameter and biomass), root morphology (total root length and root surface area), nutrient (N, P, K) contents, and photosynthetic characteristics (SPAD values, photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr)) of S. album seedlings were measured after a 3-month treatment.【Result】The height, shoot and root biomass of S. album seedlings exhibited the significantly greater growth when treated with Dalbergia odorifera root exudates, DMBQ and syringaldehyde. The total root length, root surface area and length of thin fine roots were significantly greater in S. album seedlings treated with 4 root exudates (except for B. polycarpa) and 4 chemicals than those of the control treatment. The exogenous signal substance could promote N, P and K absorption of S. album seedlings, especially for Dalbergia odorifera root exudate and DMBQ. Root exudates of Dalbergia odorifera and A. confusa, DMBQ and syringaldehyde induced significantly higher SPAD values. Dalbergia odorifera root exudate and 4 chemicals could induce significantly higher photosynthetic characteristics of S. album seedlings. The correlation analysis shows that there are significant and strong correlations between growth indices, physiology indices and root growth (except for thick fine root and coarse root length). Haustoria number of S. album seedlings are significantly correlated with the total the root length and root surface area, indicating that the haustorium development of S. album is closely related to root growth.【Conclusion】The application of root exudates of superior host and/or haustorium-inducing chemicals could effectively promote root development, nutrient absorption, and photoautotrophic capability of S. album seedlings. Our results provide insights into S. album nursery in south China.

Key words: exogenous signal substance, Santalum album, root exudates, root morphology, photosynthetic characteristics

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